Modifications to the Friedmann equation in brane cosmology can have important implications for early universe phenomena such as inflation and the generation of the baryon asymmetry. In the framework of braneworld cosmology, we discuss a mechanism for baryogenesis via leptogenesis in the supersymmetric context, where the sneutrino is responsible for both inflation and the generation of the baryo...

One of the aims of braneworld cosmology is to identify a ‘smoking gun’ for the existence of large extra dimensions by means of observations of the early universe. Braneworld cosmology has succeeded in reproducing the conventional cosmology at late times in a higher-dimensional context, but finding a unique observational signature has proved elusive. Here we demonstrate that the recently propose...

Motivated by the recent work of Saridakis [1], we generalize this work to the noninteracting case. Using an additional canonical scalar field, we formulate HořavaLifshitz cosmology with an effective interacting dark energy sector. ∗E-mail: [email protected]

We study the phase space of spatially homogeneous and isotropic cosmology in general scalar-tensor theories. A reduction to a two-dimensional phase space is performed when possible — in these situations the phase space is usually a twodimensional curved surface embedded in a three-dimensional space and composed of two sheets attached to each other, possibly with complicated topology. The result...

We study anisotropic cosmology in Hořava’s gravity theory and obtain Kasner type solutions, valid for any number d of spatial dimensions. The corresponding exponents satisfy two relations, one involving the marginal coupling λ . Also, Hořava’s (super)renormalisable theory predicts (super)stiff matter whose equation of state is p = wρ with w ≥ 1 . We discuss the implications of these results for...

The effect of a time dependent cosmological constant is considered in a family of scalartensor theories. FriedmannRobertsonWalker cosmological models for vacuum and perfect fluid matter are found. They have a linear expansion factor, the so called coasting cosmology, the gravitational ”constant” decreases inversely with time; that is these models satisfy the Dirac Hypotheses. The cosmological ”...

We link observational parameters such as the deceleration parameter, the jerk, the kerk (snap) and higher-order derivatives of the scale factor, called statefinders, to the conditions which allow to develop sudden future singularities of pressure with finite energy density. In this context, and within the framework of Friedmann cosmology, we also propose higher-order energy conditions which rel...

We examine the possibility of achieving quintessential inflation, where the same field serves as both inflaton and quintessence, in the context of a five-dimensional braneworld. Braneworld cosmology provides an appropriate environment as it permits inflation with much steeper potentials than the conventional scenario, which is favorable to a late-time quintessence. We explore a wide space of mo...